DC SSR only working at half

**jmksparks** · 07-17-2010, 06:20 PM

Thought that was the case although I seem to remember some talk about 50hz issue.

**jmksparks** · 07-17-2010, 07:23 PM

Anybody noticed that his mosfet has a zener internal as opposed to the norm of diode based, ! That is the extent of my observation

**ctmal** · 07-17-2010, 09:11 PM

I am by no means an expert but are the mosfets source and drain backwards? Also, I can't tell where the 10k resistors are going. I think they should be going between the gate and 0v.

I'm looking at the DCSSR schematic as a reference.

Somebody with more experience please chime in on this.

edit: I looked again and it does look like the 10k resistors are going between the gate and 0v.

**LabRat** · 07-17-2010, 10:10 PM

Originally Posted by dirknerkle

The Ren-C only works with a Grinch or 595 board and does not have any capability for DC or AC. The Ren-C is a translator, of sorts, that translates a serial signal into a format that the Grinch/595 can understand, which normally are connected to the parallel port.

Hang on.. something seems amiss with my understanding here.

Grinch - on/off only.. it has no idea about dimming because it has no ZC capability.
- interfaced via "clocked" in data to a latch, which controls each port.
REN-C - serial interface (does serial to clocked/latch data conversion)
- provides "DIMMING" via ZC signal passed in to it.

So if we have a version of the RENARD that is custom compiled for PWM output (when talking to DCSSRs), shouldn't such a firmware exist for the REN-C?

I'm open to be educated here. But I have to wonder, if the lack of a ZC signal couldn't result in the output being "off" for 1/2 of the duty cycle.
Manifesting as an appearance of 1/2 the voltage.

Hey.. it's just a theory.

So this REN-C... does it have a ZC signal coming into it?

**jmksparks** · 07-18-2010, 12:07 AM

Originally Posted by LabRat

Hang on.. something seems amiss with my understanding here.

Grinch - on/off only.. it has no idea about dimming because it has no ZC capability.
- interfaced via "clocked" in data to a latch, which controls each port.
REN-C - serial interface (does serial to clocked/latch data conversion)
- provides "DIMMING" via ZC signal passed in to it.

So if we have a version of the RENARD that is custom compiled for PWM output (when talking to DCSSRs), shouldn't such a firmware exist for the REN-C?

I'm open to be educated here. But I have to wonder, if the lack of a ZC signal couldn't result in the output being "off" for 1/2 of the duty cycle.
Manifesting as an appearance of 1/2 the voltage.

Hey.. it's just a theory.

So this REN-C... does it have a ZC signal coming into it?

He does say that it works for AC, I presume he means that his 240v ssr,s work with a flicker. He is most likely asleep now so will have to wait.

**soakes94** · 07-18-2010, 06:05 AM

I can control 240v ac lights and dim them which is great there is just a small flicker though. Can someone tell me what output I should be getting from the grinch as I'm getting about 2.3v at full power and I thought it would of been 5v, but I'm not sure.

Thanks for all your help

**LabRat** · 07-18-2010, 06:17 AM

I don't use a GRINCH thus I'm very much thinking of this theoretically. But it would seem that you measurement at the GRINCH is about 1/2 expected, so again I'm theorizing that your signal is actually "ON" for only 1/2 of the time. This would appear to your standard voltmeter as about 1/2 the voltage.

What are you using for your Zero Cross detection circuit? I can see in the wiki that the REN-C relies on having this signal passed to it (often from a REN-T).

Any chance you would have access to a scope, or a logic probe? If you have a PicKit2 it can be made to operate as a basic logic analyzer, and you could easily measure/watch the signal on the Grinch itself to see if it is on 100%, or if it is actually cycling on/off with a 50% duty cycle.

ps. I'm off on Holidays.. so may not be able to see the outcome of this. I *do* hope you manage to track this down soon. Best of luck... cheers.

**soakes94** · 07-18-2010, 11:26 AM

Im using a H11A1 and a 24v ac power source with the 3.3K ohm resistor on both inputs. I sadly don't have a scope or anything else like that, im 16 and new to all of this so I don't have any major equipment yet. I took a reading from all the test points on the ren-c and got these results:
Test Point 1: 4.41v
Test Point 2: 0.02v
Test Point 3: 0.02v
Test Point 4: 3.82v
Test Point 5: 0.02v

Ive got no idea what is happening, I can only think its a problem with the ren-c, but it works with AC so im not sure

Thanks everyone that has helped me with this already, I hope you guys can come up with a fix as I've got no idea what im doing

**soakes94** · 07-18-2010, 12:00 PM

Just took a reading of my 240v ac lights and Im only getting about 127v on that, so this seems to be a bigger problem than first though and I took a reading for a set of 24v ac Christmas lights and I got a 15.1v output. So its not my SSRs i dont think but either the grinch or ren-c output, as im only getting about 2.3v input to the SSR from the grinch.

Does anyone have any ideas now that its a problem over all of my SSRs? or has this made it worse?

**budude** · 07-18-2010, 12:17 PM

You mentioned you are using the H11A1 chip to generate ZC? I seem to recall you need the H11AA1 as the H11A1 only generates ZC for the half cycle where the H11AA1 does both. I'll try and find the post but I think the Wiki entry for the Ren-C ZC input was wrong and should point to the H11AA1...

Edit - yep - check this out - http://doityourselfchristmas.com/for...ighlight=H11A1